Unidirectional current system



Nov. 17, 1931. B. F. MlEssNER 1,832,646

UNIDIRECTIONAL CURRENT SYSTEM Filed May I5, ,1929

@3er www Y fat Patented Nov.y 1 7, 1931 UNITED STATES BENJAMIN E. MIESSNER, or sHoRT HILLS, NEW JERSEY, AssIGNoR, EYMEsNEAssIGN- MENTS, To RADIO CORPORATION or AMERIcA, or lNEW YORK, N. Y., A coRroRATioN n or DELAWARE f UNIDIRECTIONAL CURRENT SYSTEM Applivcam'meg may .3, 1929. serial No. 360,043.

The present invention relates to electrical unidirectional current ksupply systems, and particularly systems for supplying substantially non-fluctuating unidirectional current from sources of pulsating unidirectional'current.

A particular object is the provision of means for substantiallyl smoothing `out or filtering the strongly pulsatingV unidirectional current resulting from rectifying alternating current as, for example, the practice of energizing the electrodesA of vacuum tubes in signal current ampliers from a commercial or (S0-cycle alternating current supply system without obj ectiQnable degree of hum.

A featureof my invention is ltheemployment' of thermionic or equivalent devices as anaid in filtering the pulsations from theunidirectional currents under treatment.r

Further objects are apparent from the following description of the figuresV comprising the accompanying drawings in whichv like reference characters indicate 'corresponding parts throughout the several views, a`nd which Y. l Fig. l is a diagrammaticcircuit arrangement of one form ofmy` invention, and j Fig. '2 is a modification thereof. y Referring to the drawings, Pi designates the primary of a transformer 'T1-'connected to 4 a source A. C. of alternating current.

The transformer T1 is provided, with a plurality of low-potential three terminal secondaries S1 and S2 designed forfilament heating. The secondary S1 supplies filament heating current to a vtube VT, the characteristics of which will be described in detail hereinafter. f

y The transformer T1 is also provided with a'three terminal high potentialV secondary S3, theY outer terminals of which are connected to the anodes of a full wave rectifying tube RT, the filament of which is supplied with heating current from secondary S2. fThe-fmidpoint of the secondar S2 is connected'to Aone terminal of aloadV or systemf o fjwork. circuits through a variablev choke 4coil `L by means of leads 1 and The work circuits l may comprise for 'example' the plate` circuitsv kof a cascade Isystem ofY ampliierftubes.'

f- TheV mid-points ofthesecondariesSi, Sa, being connectedy together by a lead'f, 5 are connected to thefterminal of the loadfWby kmeansrof leads 3 and 4. The leads l and 3 serveas the terminals of a filter and storage condenser C1', The load W is preferably shunted by a. storage and by-pass con- Y denser C2. v

In Fig. 1` VT isffor example a high vacuum tube 'having a filament Fand an anodeA which vis connected to the lead 2. The filamentY E' is preferably a high temperature emissive filament of low heatl inertia sothat with potential changes occurring yin 4the secondary Sl'tlietemperature ofthe filament F and thek electronic 'emission' thereof vary, which varying emission causes the impedance of thetube VT to change. These'changesin theimpedance of the tube are so phased with relationn to` thef fluctuating component ofthe lcurrent iio'wing in the 'lead 2 that any variationY in the potential 4of the lead 2 is compensated by' anfincrease or adecrease Ain How ofcurrntthi'ough tube VT.l i In -Fig. 2, VT constitutes "a three element vacuumtube which may vbe of, the type above describe'dor of the type `shown and'd'escribed in my copending application Serialf-No. 19l,195,'led 13 May 1927, (Patent A1,718,059, June 18,1929) and having a filament F,a grid G and an anode Awhich latter is connected to the lead 2. The lead 2 also includes the primary P2 'of a transformer T2, vthe secondary S4 of which is connected between 'the grid G andthe supply source endfof a variable resistanceiR 'included in the lead 4. The mid-point of the secondary S1 in this case .is connected to the output end of the resistcrates to kproduce a ripple-free and hum-free i' source of potential at the terminals oflad kA variation in potential across the terminals of the primary?2 acts through second-V ary. Si' onto grid G to vary the impedance of u the ftub'e VT', so that the space current increases or decreases, thus varying the load between the leads 2 and 4. The transformer T2 is so poled that these variations off-set those from the source. If a tube is used in Fig. 2 having the filament characteristics of the tube specified for Fig. 1, the actiondescribed in connection with Fig. l maybe combined with the grid action to more effectively complete the filtration. `Having thus described two specific forms of my invention in which an auxiliary load across the output treminals of a full-wave rectifier is varied in definite and phased manner to neutralize or off-set any rippler or hum potential which normally would exist in the output of such a rectifier, and understanding that minor changes may be made therein but within the scope of my invention, what I Claim is v 1. In an electrical current supply system the combination of a source of fluctuating current, a work circuit supplied therefrom and means for protecting said work circuit from the fluctuating component of said source, said means consisting of a three element tube, the plateffilament circuit of which is in shunt to said work circuit, a transformer, the primary of which is series connected between the plate of said tube and said source, one terminal of the secondary of said transformer lbeing connected to the grid of said tube and the other terminal of said secondary being connected to the filament of said tube. Y

2. In an electrical current supply system the combination of a source of fluctuating current, a work circuit supplied therefrom and means for protecting said work circuit from the fluctuating component of said source, said means consisting ofv a three element tube, theplate-filament circuit of which is in shunt to said work circuit, a resistance connected between the filament of said tube and said source, a transformer, the primary of which is series connected between the plate of said tube and said source, one terminal of the secondary of which is connected to the grid of said tube and the other terminal thereof to a point in said resistance,

3. In an electrical current supply system the combination of a source of fiuctuating unidirectional current, a load to be supplied from said source, circuit connections between said source and said load, an impedance bridged across said circuit connections, and means for automatically so varying the value of said impedance in consonance with the fluctuatin currentcomponent of said source as to pro uce a permanent, liuctuating c urrent drain therethrou h of sufficient magnitude to offset said fuctuating component by reaction on said source. Y

4. In an electrical current supply system the combination of a source of fiuctuating unidirectional current,y a. load tol be supplied from said source, circuit connections between said source and said load, an impedance bridged across said circuit connections, said impedance including a therinionic tube with filamentary cathode of low thermal inertia, and means for automatically so varying the value of said impedance in consonance with the fluctuating current component of said source as to roducc a permanent, fluctuat Aing current rain therethrough of sufiicient magnitude to ofl'set said fluctuating component by reaction on said source, said means including a source of varying potential connected to said -filamentary cathode for cyclically energizing the same in consonance with the fluctuations of said source of unidirectional current whereby said impedance is varied in inverse relation to the fluctuating current component of said unidirectional source.

5. The combination with an electrical current supply system of a'source of unidirectional current having a fluctuating component, a load connected to said source for energy supply therefrom, and means for protecting said load from the fluctuating component of said source, said means co1npris ing a thermionic4 discharge tube having an anode and cathode connected in shunt to said load, said cathode being of low enough thermal inertia to permit'temperature variations therein of the frequency of said fiuctuating component and being energized from a cyclica-lly varying source of potential of such frequency and in such phase relation to the fluctuating component of said source of unidirectional current as to change the impedance of said tube between finite values in inverse order to the potential variations of said unidirectional source. 6. In an electric-current supply system the combination of a source of uni-directional current having a fluctuating component, a work circuit connected to said source for energy supply therefrom, and means for protecting said work circuit from the fluctuating component of said source, said means including a three-electrode thermionic tube the anode-cathode circuit of Whichis in shunt to said work circuit, a transformer primarily energized from said source of unidirectional current and secondarily connected for unidirectional fluctuating energization of the control electrode of said tube in such phase relation to the fiuctuating component of said source as to change the impedance of said anode-cathode circuit between finite values in inverse order to the potential variations of said source.

7. In an electric current supply system the combinationof a source of fluctuating unidirectional current,` a work circuit connected to said source for energy supply therefrom, and means for protecting said work circuit from the fiuctuating component of CFI said source, which means comprise a threeelectrode thermionic tube the anode-cathode circuit of which isin shunt to said work circuit, a transformer primarlly energized lfrom said source of unidirectional current and ysecondarily Vconnected for unidirectional fluctuating energization of the control electrode of saidtube, and a cyclically varying source of potential connected to the cathode of said tube forenergizing the saine, which cathode has a lowr enoughV thermal inertia to permit temperature variations therein of the yfrequency of said iuctuating component, said energization of the control electrode from said transformer rvsecondary and said energization of the cathode from said l varying source of potential being bothV in consonance with andin ysuch phase relation to the iuctuating component of said.' unidirectional source as to change the impedance of said anode-cathode current between finite values in inverse order to the potential variations of saidunidirectioiial source.

8. In an electric current suppl system the combination of a source of unidirectional current having a fluctuating component, a Work circuit connected'l to said source for `energy supply therefrom,` a multiple-electrode vacuum tube having an anode, a cathode, and a control electrode and having its anode-cathode circuit connected across said Work circuit, means for energizing said control electrode with a unidirectional iuctuating potential from said unidirectional cur-v rent source with the aid of an inductive coupling therewith, and means' for cyclically `energizing said cathode, which cathode is of low thermal inertia, said energizations of the control electrode and the cathode being both predeterminedly proportioned and phasedto coact in producing a resultant change of impedance in said tube of such magnitude and such phase relation with respect to said fluctuating current component a that said work circuit will be protected from l the fluctuating component of said unidirectional source. i

In witness whereof, I have hereunto subscribed iny name this Vfirst day of May, 1929.

BENJAMIN F. MIESSNER. 

